Alarms default to node['cloud_monitoring']['notification_plan_id']

We got tired of putting this everywhere and figured this was a
sensible default.
Sanity check the presence of notification_plan_id.
Bump version to 0.2.1
Merge pull request #22 from racker/make_notification_plan_default_to_data_bag

Alarms default to node['cloud_monitoring']['notification_plan_id']
Allow checks to specify entity_label attributes.

This allows checks to unambiguously refer to an
entity (similar to how alarms unambiguously refer
to their associated checks).
Bump version to 0.2.2
Merge pull request #23 from racker/add_entity_label_for_check_resource

Allow checks to specify entity_label attributes.
Allow alarms to specify entity_label as well.
Bump version to 0.2.3
Merge pull request #24 from racker/add_entity_label_for_check_resource

Allow alarms to specify entity_label as well.
Add build-essential package for Debian/Ubuntu

rackspace-monitoring depends on rackspace-fog which depends on fog which
depends on nokogiri. Nokogiri needs a working build system to install.

I'm not sure and couldn't find reliable info on what the Redhat/CentOS
equivalent would be so I haven't added that.
Bump version to 0.2.4
Merge pull request #25 from racker/install_build_essentials

Add build-essential package for Debian/Ubuntu
Added missing auth url to the lwr for entity
If the chef_gem resource fails always fall back to system level ruby
Make credentials configurable

* Anywhere the encrypted databag was used now has a configurable node attribute to find the
data bag. Will fallback to the old default if not specified.
Updated per feedback

* Changed the name of the databag to be databag_name and databag_item
* Set defaults in the attributes to be overriden
Make system ruby install a flag

By default, we don't use the system ruby install and one has to make
the conscious decision to do so.
Add missing resource attributes